Can someone explain the difference between chromosomal and genetic testing?

[TheTimeTravellersWife]

DD has had tests for chromosomal abnormalities, such as Fragile X, which all came back clear.
Her Paed is talking about genetic testing and I don't understand the difference between this and the chromosomal tests already carried out.
Is this just another blood test? Will DH and myself have a blood test too? Will DS need a blood test?

Will it possibly show up something that the chromosmal testing has missed?

I would be so grateful if someone who has been through this could tell me about it! Was it worth doing?

I didn't know there was a difference, so will watch this thread with interest. DS has only just last week had the all clear for chromosomal testing (including Fragile X) but as far as his paed's concerned, that's the blood tests out of the way; the only thing he did say might be on the cards were maybe skin biopsies but that he's not wading in with that just yet.

Sorry I can't be of any help. Good news that you've got the all clear from the chromosome testing, it's an agonising wait, isn't it!

Ditto.... i too thought they were the same thing! hmmmm

hope someone can help out xxx

This is going back a little bit now, but ds had the chromosome testing as your dd has had, but when that was all fine I think he had the FISH test & the microarray (?? spellings & they might be one in the same)... but these test for much smaller problems on the strands. In my ds's case he was missing a section right below the tip of one of the chromosomes and these further tests picked it up and led to his diagnosis.

it is the same thing. There's just many different levels within genetics, it's worth looking at unique as they can explain things much better than me! It sounds like your dd has had some of the basic genetic testing that is looking for something specific where only one thing will be looked for, so the results from that will only tell you if your child has the thing they were testing for. If nothing comes up here then they may still think there is something genetic going on but are not sure what, so have to start looking at everything rather than something specific. Again there are levels within this, so they may start with karotyping that looks at all the chromosomes under the microscope and will pick up any more obvious differences. I think currently the most detailed test is comparative genome hybridisation/microarray that breaks all the chromosomes down into thousands of parts and can pick up much smaller differences. Even then they still can't pick up everything, it doesn't completely rule out a genetic issue if they can't find anything.

who ends up having blood tests very much depends on what, if anything they find. It was worth it for us even though we didn't find the specific cause of dd3's syndrome but it's each to their own I think on what's right for you.

Thanks for explaining. I will go and have a look on the Unique website.

I have this nagging doubt in the back of my mind because we have never got to the bottom of DD's problems. She has microcephaly, ASD, Attention Deficit, dyspraxia, MLD, speech and language problems, but at the moment there is no one cause identified for these conditions.

Despite the microcephaly, she has never had a brain scan either; the paed put us off saying that it would be traumatic for her and that it wouldn't change anything.

But increasingly, I just want to know and at least have some answers, but the Paed is dismissive of this view; I'm thinking of pushing for a referral to GOSH, but torn really between just accepting DD for who she is and wanting to know WHY she is the way she is!

TheTimeTravellersWife

The real issue is that for many of the issues our children have there are as yet no specific answers, international research is still a long way from even having the technology to identify the real causes of these types of problems.

Genetic research is still in its infancy, and at best the researchers are talking about candidate genes, or large groups of genes which can be considered as being responsible for most of these problems. There are a few exceptions such as Fragile X where a specific genetic issue has been identified.

The other problem is the lack of joined up thinking between thew various researchers, the multitude of type of professions involved in the diagnostic processes, most of whom do not communicate with each other, and that is in the medical professions. This before you consider the lack of training and a professional research based understanding required to run the UK education system, which is well intentioned amateurism at best.

So the best approach is to try to understand in depth, best from international research sources, and try to understand the existing diagnosed issues as best you can. The ideal answers we all are searching for are years away from existing as medical research still has a long way to go to begin to have the beginnings of a comprehensive explanations we ideally need.

I have been researching our families diagnosed disabilities for over 14 years now, and at this point because we live with the disability we have a better understanding of the issues than the researchers and professionals we have been in contact with over the years, and that includes both the UK Medical Research Council and GOSH.

what might your dd ask in the future? Would you like to ahve some answers for her. Whatever her ability she may have a need/want to know more as she gets older?
If it were you or I we would be able to ask for reasons/explanations, there may not be an answer but until you are satisfied that all the basic tests (including MRI) have been done you will always be wondering... Push for that test.